Good common sense says that if you have eight shots to bag supper, then you don't waste one on target practice -- unless there is already somethin' in the bag.
So the squiggly lines ( thermograms ) can't be read at all until Phoenix is burried up to its, er, solar panels in CO2 show?
The instrument's results seems particularly simple to an old particle physicists eyes: particle count vs. energy.
If I understand the instrument correctly, the mass spectrometer has been "tuned" for isotopes of carbon, nitrogen, oxygen and hydrogen ( 10 parts per billion detection ) so if all thermograms show a peak at, say, 140.25 C then there are only a limited number of molecules containing C, N, O and H that could become gases at that temperature.
So the exact molecule might take some analysis, but the fact that some organic molecule was detected would be immediately apparent.
Here is an intresting paper discussing how the TEGA thermograms can be used to test the super-oxide theory.
Anyway, the OFB is sampled.